Spinal correction system actuators

ABSTRACT

A spinal correction system for implantation in a patient, the system including a reciprocating adjuster and/or a resistance adjuster coupled to a stabilizing member, for example. The resistance adjuster includes a potential energy drive, a slide unit, and a resistance unit. The reciprocating adjuster includes a piston unit, a transfer unit coupled to the piston unit, and a return mechanism.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a national phase application of PCT applicationPCT/US2012/040493, internationally filed Jun. 1, 2012 and entitled“SPINAL CORRECTION SYSTEM ACTUATORS”, which claims priority to U.S.Provisional Application No. 61/493,117, filed on Jun. 3, 2011 andentitled “SPINAL CORRECTION SYSTEM ACTUATORS”, the entire contents ofwhich is incorporated herein by reference for all purposes.

BACKGROUND

Many systems have been utilized to treat spinal deformities such asscoliosis, spondylolisthesis, and a variety of others. Primary surgicalmethods for correcting a spinal deformity utilize instrumentation tocorrect the deformity as much as possible, as well as implantablehardware systems to rigidly stabilize and maintain the correction. Manyof these implantable hardware systems rigidly fix the spinal column orallow limited growth and/or other movement of the spinal column, to helpfacilitate fusion after the column has been moved to a correctedposition.

SUMMARY

Some inventive aspects relate to a spinal correction system forimplantation in a patient, the system including a reciprocating adjusterand/or a resistance adjuster coupled to a stabilizing member, forexample. In some embodiments, the resistance adjuster includes apotential energy drive, a slide unit, a and a resistance unit. In someembodiments, the reciprocating adjuster includes a piston unit, atransfer unit coupled to the piston unit, and a return mechanism.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a system for correcting a spine tending to exhibit a spinaldeformity, according to some embodiments.

FIG. 2 shows a correction anchor and connector of the system of FIG. 1,according to some embodiments.

FIG. 3 shows a top view of a tensioner and a stabilizing member of thesystem of FIG. 1, according to some embodiments.

FIG. 4 shows the tensioner of FIG. 3 with a portion of a housing of thetensioner removed, according to some embodiments.

FIGS. 5 and 6 show a tensioning system for externally actuating one ormore of the tensioners of the system of FIG. 1, following implantationof the system, according to some embodiments.

FIGS. 7 and 8 show another tensioning system for externally actuatingone or more of the tensioners of the system of FIG. 1, followingimplantation of the system, according to some embodiments.

FIGS. 9 and 10 show another tensioning system that is optionallyemployed in addition to, or as a replacement for, one or more of thetensioners, according to some embodiments.

FIGS. 11 and 12 show another tensioning system that is optionallyemployed in addition to, or as a replacement for, one or more of thetensioners, according to some embodiments.

FIGS. 13, 14, and 15 show another tensioning system that is optionallyemployed in addition to, or as a replacement for, one or more of thetensioners, according to some embodiments.

FIGS. 16 and 17 show another tensioning system that is optionallyemployed in addition to, or as a replacement for, one or more of thetensioners, according to some embodiments.

FIGS. 18 and 19 show another tensioning system that is optionallyemployed in addition to, or as a replacement for, one or more of thetensioners, according to some embodiments.

FIGS. 20 and 21 show another tensioning system that is optionallyemployed in addition to, or as a replacement for, one or more of thetensioners, according to some embodiments.

FIGS. 22, 23 and 24 show another tensioning system that is optionallyemployed in addition to, or as a replacement for, one or more of thetensioners, according to some embodiments.

FIGS. 25 and 26 show another tensioning system that is optionallyemployed in addition to, or as a replacement for, one or more of thetensioners, according to some embodiments.

FIGS. 27 and 28 show an expanding stabilizing member system that isoptionally employed in addition to, or as a replacement for, thestabilizing member of the system of FIG. 1, according to someembodiments.

FIG. 29 shows another tensioning system that is optionally employed inaddition to, or as a replacement for, one or more of the tensioners,according to some embodiments.

FIGS. 30 and 31 show a first actuator collar of the system of FIG. 29,where FIG. 30 shows the first actuator collar in a free spinning, orunlocked state, and FIG. 31 shows the first actuator collar in a locked,or engaged state, according to some embodiments.

FIG. 32 shows another tensioning system that is optionally employed inaddition to, or as a replacement for, one or more of the tensioners,according to some embodiments.

FIGS. 33 and 34 show another tensioning system that is optionallyemployed in addition to, or as a replacement for, one or more of thetensioners, according to some embodiments.

FIGS. 35 and 36 show another tensioning system that is optionallyemployed in addition to, or as a replacement for, one or more of thetensioners, according to some embodiments.

FIGS. 37 and 38 show another tensioning system that is optionallyemployed in addition to, or as a replacement for, one or more of thetensioners, according to some embodiments.

FIGS. 39, 40, and 41 show an expanding stabilizing member system that isoptionally employed in addition to, or as a replacement for, thestabilizing member of the system of FIG. 1, according to someembodiments.

FIGS. 42, 43, and 44 show an expanding stabilizing member system that isoptionally employed in addition to, or as a replacement for, thestabilizing member of the system of FIG. 1, according to someembodiments.

FIGS. 45 and 46 show another tensioning system that is optionallyemployed in addition to, or as a replacement for, one or more of thetensioners, according to some embodiments.

While the invention is amenable to various modifications and alternativeforms, specific embodiments have been shown by way of example in thedrawings and are described in detail below. The intention, however, isnot to limit the invention to the particular embodiments described. Onthe contrary, the invention is intended to cover all modifications,equivalents, and alternatives falling within the scope of the inventionas defined by the appended claims.

DETAILED DESCRIPTION

Some embodiments relate to a system for correcting spinal deformities,as well as associated methods and devices. In general terms, the systemprovides lateral translational corrective force(s) and/or derotationalcorrective force(s) on a spinal column tending to exhibit a defectivecurvature. In some embodiments, the system facilitates incrementalcorrection, gross correction, and/or correction maintenance as desired.

Various planes and associated directions are referenced in the followingdescription, including a sagittal plane defined by two axes, one drawnbetween a head (superior) and tail (inferior) of the body and one drawnbetween a back (posterior) and front (anterior) of the body; a coronalplane defined by two axes, one drawn between a center (medial) to side(lateral) of the body and one drawn between the head and tail of thebody; and a transverse plane defined by two axes, one drawn between aback and front of the body and one drawn between a center and side ofthe body.

Also, the terms pitch, roll, and yaw are used, where roll generallyrefers to angulation, or rotation, in a first plane through which alongitudinal axis of a body orthogonally passes (e.g., rotation about alongitudinal axis corresponding to the spinal column), pitch refers toangulation, or rotation, in a second plane orthogonal to the firstplane, and yaw refers to angulation, or rotation, in a third planeorthogonal to the first and second planes. In some embodiments, pitch isangulation in the sagittal plane, yaw is angulation in the coronalplane, and roll is angulation in the transverse plane. In variousembodiments, changes in pitch, yaw, and/or roll occur concurrently orseparately as desired. Moreover, as used herein, “lateral translation”is not limited to translation along the medial-lateral axis (in eitherthe lateral-medial or medial-lateral direction(s)) unless specified assuch.

FIG. 1 is a perspective view of a system 10 for correcting a spinetending to exhibit a spinal deformity, according to some embodiments. Asshown in FIG. 1, the system 10 includes a stabilizing member 12; aplurality of stabilizing anchors 14, including a first stabilizinganchor 14A and a second stabilizing anchor 14B; a plurality ofcorrection anchors 18 including a first correction anchor 18A and asecond correction anchor 18B; a plurality of tensioners 20 including afirst tensioner 20A and a second tensioner 20B; and a plurality ofconnectors 22 including a first connector 22A and a second connector22B. As shown, the system 10 is secured to a spinal column 24 formed ofa plurality of vertebrae 26, including a first vertebra 26A, a secondvertebra 26B, a third vertebra 26C, and a fourth vertebra 26D.

In some embodiments, the stabilizing member 12 is also referred to as arod or alignment member; the stabilizing anchors 14 are also referred toas alignment supports or guides; the correction anchors 18 are alsoreferred to as anchor arms or vertebral levers, the tensioners 20 arealso referred to as adjustment mechanisms or tying devices, and theconnectors 22 are also referred to as force directing members or cables,for example. Although the system 10 is shown with two stabilizinganchors 14, two correction anchors 18, two tensioners 20, and twoconnectors 22, a greater or fewer number thereof are implemented asappropriate. As described in greater detail below, the tensioners 20and/or stabilizing member 12 are optionally replaced and/or augmented bya variety of other tensioning and expanding stabilizing member systems.

Some examples of suitable stabilizing members 12, stabilizing anchors14, correction anchors 18, tensioners 20, and/or connectors 22 accordingto some embodiments are described in U.S. application Ser. No.12/411,562, filed Mar. 26, 2009, and entitled “Semi-ConstrainedAnchoring System”; U.S. application Ser. No. 11/196,952, filed Aug. 3,2005, and entitled “Device and Method for Correcting a SpinalDeformity”; and U.S. application Ser. No. 12/134,058, filed Jun. 5,2008, and entitled “Medical Device and Method to Correct Deformity,” theentire contents of each which are incorporated herein by reference forall purposes.

As shown, the spinal column 24 has a transverse centerline of rotationY, also described as a longitudinal axis of rotation. In someembodiments, the transverse centerline rotation Y of the spinal column24 generally corresponds to a mid-distance position of the spinal canal(not shown) extending through the spinal column 24, where each vertebra26 has a transverse center of rotation generally located on thetransverse centerline of rotation Y.

As shown in FIG. 1, the correction anchors 18 are fixed to a targetregion 24A of the spinal column 24 tending to exhibit an abnormal, ordefective curvature (e.g., scoliosis) in need of correction. The system10 is optionally used to apply derotational and/or lateral translationalforces on the target region 24A of the spinal column 24 to translateand/or maintain the spinal column 24 at a desired curvature.

In some embodiments, the stabilizing member 12 is substantially elongateand rigid, and, if desired, the stabilizing member 12 incorporates someflex, or springiness while substantially rigidly retaining its shape. Aswill be described in greater detail, the stabilizing member 12 isadapted, or otherwise structured, to extend along the spinal column 24at a desired spacing from the vertebrae 26 of the spinal column 24. Insome embodiments, the stabilizing member 12 is partially or fullycontoured to a typical, corrected curvature of the spinal column 24. Thestabilizing member 12 has a longitudinal axis X and where thestabilizing member 12 is substantially straight, the longitudinal axis Xis substantially straight. Where the stabilizing member 12 has curved orangled portions, the longitudinal axis X at those portions is similarlycurved or angled. As described in greater detail, the stabilizing member12 optionally includes features for adjusting a length of thestabilizing member 12.

FIG. 1 shows the pair of stabilizing anchors 14A, 14B which are adapted,or otherwise structured, to be mounted or fixed to one or morestabilizing vertebrae, such as the first and second vertebrae 26A, 26B.The first and second stabilizing anchors 14A, 14B are further adapted toreceive, and include means for receiving, the stabilizing member 12 suchthat the stabilizing member 12 is secured laterally, against lateraltranslation relative to the first and second stabilizing anchors 14A,14B.

In some embodiments, the stabilizing anchors 14 are secured to a singleone of the vertebra 26 (e.g., laterally across the vertebra at thepedicles, or at a single point, such as a single pedicle). The first andsecond stabilizing anchors 14A, 14B are each secured to a singlevertebra in some embodiments or multiple vertebrae in others, such as anadditional, adjacent one of the vertebra 26. As shown in FIG. 1, thefirst and second stabilizing anchors 14A, 14B are secured to the firstand second vertebrae 26A, 26B, respectively, as well as one of thevertebrae 26 adjacent each of the first and second vertebrae 26A, 26B.As received by the first and second stabilizing anchors 14A, 14B, thestabilizing member 12 is semi-constrained by the stabilizing anchors 14,the stabilizing member 12 being free to move with natural movements ofthe spinal column 24 while being substantially prevented fromtranslating in a direction that is substantially perpendicular to thelongitudinal axis X of the stabilizing member 12 at each of thestabilizing anchors 14A, 14B.

In some embodiments, the stabilizing member 12 is able to slide axially,or translate axially in one or two directions, along the longitudinalaxis X, relative to the first and/or second stabilizing anchors 14A,14B. The stabilizing member 12 is able to slide and to change in atleast pitch and yaw at the first and second stabilizing anchors 14A,14B. If desired, the stabilizing member 12 is also able to change inroll at the first and/or the second stabilizing anchors 14A, 14B. Thus,in some embodiments, the stabilizing anchors 14 are adapted to receivethe stabilizing member 12 and secure the stabilizing member 12 againstsubstantial lateral translation relative to stabilizing vertebrae (e.g.,the first and second vertebrae 26A, 26B). For example, the vertebrae26A, 26B (as well as secondary vertebra to which the stabilizing anchors14 are secured) are used to stabilize the stabilizing member 12 whichdefines a line of reference from which to adjust defective curvature byproviding a series of anchor points toward which the target region 24Ais able to be pulled.

The first and second correction anchors 18A, 18B are optionallysubstantially similar, and thus various features of the secondcorrection anchor 18B are described in association with the firstcorrection anchor 18A. Features of the first correction anchor 18A aredesignated with reference numbers followed by an “A” and similarfeatures of the second correction anchor 18B are designated with similarreference numbers followed by a “B.”

FIG. 2 shows the first correction anchor 18A according to someembodiments. As shown, the first correction anchor 18A is generallyL-shaped, where the first correction anchor 18A includes an arm 50A withoptional threading 51A (shown in broken lines) and a head 52A assembledto one another in a generally L-shaped configuration. The firstcorrection anchor 18A is optionally substantially rigid. In someembodiments, the arm 50A extends from the head 52A to a terminal coupler54A and is disposed generally perpendicular to the head 52A. In someembodiments, a length of the correction anchor 18A is adjustable, asdescribed in greater detail below. The arm 50A is optionally securedabout, and rotatable relative to the head 52A and is adapted to extendacross one of the vertebrae 26, for example, from one side of the spinalcolumn 24 to an opposite side of the spinal column 24.

The head 52A of the correction anchor 18A is optionally adapted orotherwise structured to be fixed to a portion of the third vertebra 26C,such as a pedicle of the third vertebra 26C. The head 52A includes abody portion 56A and a cap portion 58A. The head 52A includes and/or isadapted to work in conjunction with any of a variety of means forsecuring to the third vertebra 26C. For example, the body portion 56A isoptionally configured as a pedicle screw. Assembly of the firstcorrection anchor 18A includes receiving the arm 50A on the body portion56A of the head 52A and screwing or otherwise securing the cap portion58A onto the body portion 56A. In some embodiments, the arm 50A isrotatable relative to the head 52A upon assembly of the correctionanchor 18A.

The first correction anchor 18A is secured to the third vertebra 26Csuch that the arm 50A extends across the third vertebra 26C eitheradjacent to the spinous processes or through a hole or hollowed portionin the spinous processes of the third vertebra 26C. In some embodiments,the second correction anchor 18B is secured to the fourth vertebra 26D,where the fourth vertebra 26D is an apical vertebra at the apex A of thetarget region 24A (FIG. 1).

The first tensioner 20A is shown in FIGS. 3 and 4, where FIG. 4 showsthe first tensioner 20A with a portion removed to illustrate innerfeatures thereof. The tensioners 20 are optionally substantiallysimilar, and thus various features of the first, and second tensioners20A, 20B are described in association with the first tensioner 20A.Features of the first tensioner 20A are designated with referencenumbers followed by an “A” and similar features of the second tensioner20B are designated with similar reference numbers followed by a “B.”

Generally, the first tensioner 20A provides means for securing the firstconnector 22A to the stabilizing member 12. In some embodiments, thefirst tensioner 20A, also described as an adjustment mechanism orcoupler, is further adapted to adjust, and provides means for adjustingthe effective length of the first connector 22A.

In some embodiments, the first tensioner 20A includes a reel 70A havinga central lumen adapted to be coaxially received over the stabilizingmember 12, a circumferential gear 72A surrounding the reel 70A, avertical gear 74A in contact with the circumferential gear 72A, anactuation head 78A, and a housing 80A.

The reel 70A, as well as the circumferential gear 72A and vertical gear74A are maintained at least partially within the housing 80A. In turn,the housing 80A is adapted to be secured to the stabilizing member 12.For example, the housing 80A optionally forms a clamshell configurationthrough which the stabilizing member 12 is receivable. Upon insertingthe stabilizing member 12 through the central lumen of the reel 70A, thehousing 80A is adapted to be clamped onto the stabilizing member 12 withthe reel 70A free to rotate about the stabilizing member 12.

The first connector 22A is attached or secured to the reel 70A andpasses out of the housing 80A through an appropriately sized opening inthe housing 80A. Actuation of the vertical gear 74A via the actuationhead 78A turns the circumferential gear 72A, which turns the reel 70A,thus winding (or unwinding, depending on the direction in which the reel70A is turned) the first connector 22A about the reel 70A. Rotation ofthe reel 70A in the appropriate direction draws the first connector 22Ain toward the first tensioner 20A, pulling the first correction anchor18A (FIG. 1) toward the first tensioner 20A according to some methods ofcorrecting a spinal defect. In some embodiments, the actuation head 78Ahas a receptacle for receiving a hex head driver for rotating theactuation head 78A.

From the foregoing, it should also be understood that the secondconnector 22B is similarly coupled to the second tensioner 20B, whereactuation of the second tensioner 20B modifies the effective length ofthe second connector 22B, drawing the connector 22B in or letting themout.

The connectors 22A, 22B are optionally substantially similar, and thusvarious features of the connectors 22 are described in association withthe first connector 22A. Features of the first connector 22A aredesignated with reference numbers followed by an “A” and similarfeatures of the second connector 22B are designated with similarreference numbers followed by a “B.”

In some embodiments, the first connector 22A is substantially flexiblesuch that the first connector 22A is able to be pivoted in multipledirections (e.g., to facilitate a polyaxial connection to the correctionanchor 18A and/or the tensioner 20A). Such flexibility additionally oralternatively facilitates spooling or winding of the first connector22A, for example. Suitable flexible materials for forming the firstconnector 22A include wire and stranded cables, monofilament polymermaterials, multifilament polymer materials, multifilament carbon orceramic fibers, and others. In some embodiments, the first connector 22Ais formed of stainless steel or titanium wire or cable, although avariety of materials are contemplated.

As shown in FIG. 1, the first connector 22A, also described as a forcedirecting member or a cable, is adapted to be secured to the firstcorrection anchor 18A and the first tensioner 20A, the first connector22A defining an effective length between the first tensioner 20A and thefirst correction anchor 18A, and thus the stabilizing member 12(although, in some embodiments, the first connector 22A is secureddirectly to the stabilizing member 12). As described, in someembodiments, the first tensioner 20A is adapted to modify, and providesmeans for modifying, the effective length of the first connector 22A. Asshown, the second connector 22B interacts similarly with the secondcorrection anchors 18B.

In view of the foregoing, assembly and use of the system 10 according tosome embodiments generally includes attaching the stabilizing anchors 14on superior and/or inferior locations of the target region 24A, forexample to transitional vertebrae characterizing a scoliotic curvatureof the spinal column 24. In some embodiments, the target region 24Aincludes those of the vertebrae 26 in need, or in greater need, ofcorrection. In operation, the connectors 22 couple the correctionanchors 18 to the stabilizing member 12 and, by retracting theconnectors 22 toward the stabilizing member 12, the spinal column 24 isbrought into more natural alignment.

The system 10 is optionally used for incremental correction, for grosscorrection, and/or for maintaining a correction as desired. For example,the connectors 22 are optionally retracted incrementally as part of oneor more procedures using the tensioners 20. In other embodiments, asingle, gross adjustment is made using the tensioners 20 or otherdevice(s) to accomplish a desired correction. In still otherembodiments, a correction is made using other hardware, prior to or inconjunction with securing the system 10 to the spinal column 24, wherethe system 10 is utilized to maintain the desired correction.

FIGS. 5 and 6 show a tensioning system 100 for externally actuating oneor more of the tensioners 20 following implantation of the system 10. Asshown, the tensioning system 100 includes an implantable driver 102,also described as a reciprocating adjuster, and an external driver 104.

In some embodiments, the implantable driver 102 includes a housing 106,one or more lever arms 108, also described as piston units, maintainingone or more magnet(s) 110 and defining a center of rotation within thehousing 106, a drive shaft 112 coaxial with the center of rotation ofthe lever arms 108, a one-way roller clutch 114 connected to the driveshaft 112, and reset springs 115 (FIG. 6), also described as a returnmechanism. The drive shaft 112 is adapted to couple with the actuationhead 78A, for example by including a suitable mating component, such asa hex head driver, or by being integrally formed or otherwise connectedto the actuation head 78A such that displacement of the lever arms 108in a first direction causes the reel 70A to rotate in a second,orthogonal direction such that the tensioner 20A acts as a transferunit. In some embodiments, the housing 106 of the implantable driver 102is secured to the housing 80A, for example being integrally formedtherewith.

The external driver 104 is configured to activate the implantable driver102 through the body of a patient (e.g., through skin, muscle, and/orbone as appropriate) and includes a housing 120, a drive assembly 122, adrive shaft 124 connected to the drive assembly 122, and a magnetassembly 126 connected to the drive shaft 124. In use, activation of thedrive assembly 122 causes the magnet assembly 126 to rotate.

The drive assembly 122 is optionally an angle driver adapted to rotatethe drive shaft 124 at a desired speed and torque. The housing 120 isoptionally substantially cylindrical in shape and includes a top 128 anda bottom 130, the housing including a central aperture for receiving thedrive shaft 124 and being sized and shaped to receive the magnetassembly 126 such that the magnet assembly 126 is free to rotate withinthe housing 120.

The magnet assembly 126 includes a plurality of magnets, such as a firstmagnet 126A of a first polarity and a second magnet 1268 of the same, oran opposite polarity. As shown in FIG. 5, the first and second magnets126A, 126B are connected to one another with a circular attachment 128that is, in turn, connected to the drive shaft 124, the drive shaft 124being coaxial with an axis of rotation of the magnet assembly 126. Thefirst and second magnets 126A, 126B are optionally diametrically opposedto one another relative to the axis of rotation of the magnet assembly126.

In some uses, the implantable driver 102 is operated, or magneticallypowered, through the skin S of a patient using the external driver 104.In particular, as the first and second magnets 126A, 126B of theexternal driver 104 rotate, the magnet(s) 110 of the implantable driver102 are rotated until the magnet(s) 110 are unable to rotate further(e.g., with the housing 106 acting as a stop). The one-way roller clutch114 allows rotation in a single direction and, upon reaching the limitof rotation, the magnet(s) 110 reset back to their original position viaspring-action before the next one of the first and second magnets 126A,126B rotates into position with one or more of the magnet(s) 110 toinitiate another ratchet sequence. The one-way roller clutch 114 isadapted to ratchet, or hold, after a small amount of rotation. Thishelps allow a relative compact design, as the lever arms 108 are notrequired to travel through a large rotational angle. For example, thelever arms 108 optionally each travel through an angle of between 0 and45 degrees or between 5 and 30 degrees, although a variety of angularlimits are contemplated. In some embodiments, a gearing system (notshown) is also employed to help increase torque as desired. The housing106 of the implantable driver 102 and the housing 120 of the externaldriver 104 help avoid unwanted contact of moving parts with the skin ofthe patient.

FIGS. 7 and 8 show another tensioning system 150 for externallyactuating one or more of the tensioners 20 following implantation of thesystem 10. As shown, the tensioning system 150 acts as a reciprocatingadjuster and includes a cap 152, also described as a piston unit, and aspring 154, also described as a return mechanism, as well as a one-waydrive roller clutch 156 and a drive shaft 158, also described as atransfer unit. The tensioning system 150 is adapted to translate alinear downward force to lateral, or transverse, rotation. The cap 152is engaged with the spring 154 and one-way drive clutch 156 such thatwhen a downward force is applied to the spring-loaded cap 152 theensuing downward movement of the cap 152 causes lateral rotation of theone-way drive roller clutch 154. In some embodiments, the clutch 156 hasgrooves or ridges 156A that are cut at an angle so that depression ofthe cap 152 causes the clutch 156 to rotate, where the steeper the anglethe less the force required to depress the cap 152 and the less ensuingrotation of the drive shaft 158. The drive shaft 158 and/or clutch 156are also optionally coupled to a gearbox (not shown) to enhancemechanical advantage of the system 150. The system 150 also optionallyincludes a plurality of low-friction ball bearings 160 between the cap152 and the clutch 156 to reduce the force needed to depress the cap 152and rotate the drive shaft 158.

The one-way drive roller clutch 156 is coupled to the drive shaft 158such that rotation of the clutch 156 translates to rotation of the driveshaft 158. In some embodiments, the drive shaft 158 is adapted to beconnected to the actuation head 78A. The drive shaft 158 is optionally a4 mm hex drive adapted, for example, to engage with a female 4 mm hexpocket in the actuation head 78A of the tensioner 20A (FIG. 1).

The system 150 is optionally activated by depressing the button througha patient's skin, where the cap 152 is located by a user via tactilefeel and/or external markings (e.g., tattoos), for example. In someembodiments, during use, the cap 152 does not rotate relative to thetensioner 20A. For example, the downward force on the cap 152 rotatesthe one-way roller clutch 156, which then actuates the tensioner 20A totighten the connector 22A, for example.

FIGS. 9 and 10 show another tensioning system 200, also described as areciprocating adjuster, that is optionally employed in addition to, oras a replacement for, one or more of the tensioners 20. The tensioningsystem 200 includes a housing 202, an outer one-way roller clutch 204,also referred to as an outer clutch, an inner one-way roller clutch 206,also referred to as an inner clutch, a push button 208, also describedas a piston unit, and a spring 210, also described as a returnmechanism. The housing 202 generally maintains the outer and innerclutches 204, 206, also described as a transfer unit, the push button208 and the spring 210, and is adapted to be secured (e.g., via aclamshell fit) to the stabilizing member 12. As shown in FIG. 10, theouter clutch 204 includes gearing 212 and the push button 208 includesgearing 214, the gearing 212 and the gearing 214 being adapted tocomplement one another to rotationally drive the outer clutch 204 upondepressing the push button 208, where linear movement of the push buttonis translated into transverse movement of the outer clutch 204.

As designated in FIG. 10, the outer clutch 204 is adapted to spin freelyin a first direction D1 and to lock to the inner clutch 206 in a seconddirection D2. In turn, the inner clutch 206 is adapted to spin freelyrelative to the stabilizing member 12 in the second direction D2 whilebeing locked to the stabilizing member 12 in the first direction D1.

In some embodiments, the outer and inner clutches 204, 206 are one-waydrawn-cup roller clutches arranged with the outer clutch 204 around theinner clutch 206 such that when the push button 208 is depressed boththe inner roller clutch 206 and the outer clutch 204 forward rotaterelative to the stationary member and when the push button is released208 the spring 210 returns the push button 208 to its original positionand the inner clutch 206 remains stationary while the outer clutch 204back rotates relative to the stabilizing member 12.

One of the connectors 22, for example the connector 22A, is secured tothe inner clutch 206 such that a user accessing the push button 208(e.g., through the skin of a patient as previously described) is able torepeatedly push the push button 208 in order to ratchet the connector22A toward (or alternatively, away) from the stabilizing rod 12,shortening the effective length of the connector 22A. Gear boxes orother means of enhancing mechanical advantage of the system 200 areemployed as desired.

FIGS. 11 and 12 show another tensioning system 250, also described as areciprocating adjuster, that is optionally employed in addition to, oras a replacement for, one or more of the tensioners 20. As shown,similarly to the system 200, the system 250 also employs a dual rollerclutch mechanism, also described as a transfer unit. The system 250includes a housing 252, an outer one-way roller clutch 254, alsoreferred to as an outer clutch, an inner one-way roller clutch 256, alsoreferred to as an inner clutch, a push button 258, also referred to as apiston unit, a spring 260, also described as a return mechanism, and adrive linkage 262 coupling the push button 258 to the outer clutch 254.In operation, depression of the push button 258 results in rotationalforce on the outer clutch 254 in a first direction and releasing thepush button 258 from the depressed position to an initial positionresults in a rotational force on the outer clutch 254 in an oppositedirection. The housing 252 generally maintains the outer and innerclutches 254, 256, the push button 258, the spring 260, and the drivelinkage 262, and is adapted to be secured (e.g., via a clamshell fit) tothe stabilizing member 12. As shown, the system 250 also includes amagnetic latch assembly 270 adapted to allow selective activation of thesystem 250 for adjustment.

In some embodiments, the system 250 generally operates similarly to thesystem 200, where a user depresses the push button 258 through the skinof the patient to ratchet one of the connectors 22, for example thefirst connector 22A, around the inner clutch 254. Additionally, themagnetic latch assembly 270 is present as an optional feature to helpprevent inadvertent adjustment of the system 250 (e.g., by anunintentional depression of the push button 258). As shown, the magneticlatch assembly 270 includes a housing 271 maintaining a spring 272, alatch magnet 274, and a stop member 276 adapted to engage with stopfeatures 280 associated with the inner clutch 206 (e.g., slots formedinto the outer surface of the inner clutch 206).

The magnetic latch assembly 274 is operated by bringing a magnet inclose enough proximity to the latch magnet 274 to release the stopmember 276 from the stop features 280. Upon doing so, the push button258 is able to be depressed to ratchet the system 250.

Thus, the system 250 provides a relatively vertical, or in-linearrangement of a dual roller clutch mechanism, where the push button 258is more in line with the stabilizing member 12 to help minimize theamount of lateral space taken up by the design. In some embodiments, themagnetic latch assembly 274 helps prevent rotation unless a magnet isplaced above the latch magnet 274, thereby helping to preventunintentional activation of the tensioning system 250. In use, a user(not shown) would bring an external magnet into proximity with the latchmagnet to put the system 250 into an active state and then operate thesystem 250 with the system 250 in the active state.

FIGS. 13, 14, and 15 show another tensioning system 300 that isoptionally employed in addition to, or as a replacement for, one or moreof the tensioners 20. As shown, the system 300, also described as aresistance adjuster and a reciprocating adjuster, includes a housing302, a drive member 304, also described as a slide unit, a drive spring306, also described as a potential energy drive, a reset spring 310(FIG. 15), also described as a return mechanism, and a push button 308and an engagement member 312, also described as a resistance unit.

The housing 302 is optionally substantially cylindrical and hollow,defining a first compartment 302A and a second compartment 302B. Thedrive member 304 extends from the first compartment 302A out of thesecond compartment 302B of the housing 302, where the drive member 304and the housing 302 are coaxially received over the stabilizing member12. The drive member 304 is optionally substantially cylindrical andhollow and defines an enlarged base 316, a main body 318, and anenlarged head 320. The main body 318 includes a plurality of teeth 322(FIG. 15) adapted to selectively engage with the engagement member 312.

As shown in FIGS. 13 and 14, the drive member 304 is adapted to slideover the stabilizing member 12 while the housing 302 is secured relativethereto, the drive member 304 being able to slide out from the housing302 until the enlarged head limits further travel of the drive member304. As shown, the drive spring 306 is coaxially received over the drivemember 304 between the base 316 and the housing 302. The drive spring306 is a compression spring for exerting a pushing force on the base 316of the drive member 304, to move the drive member 304 from a firstposition (FIG. 13) to a second position (FIG. 14) away from the housing302, although other types of potential energy drives are contemplated.

As shown in FIG. 15, the push button 308 is slidably received through asidewall of the second compartment 302B and is connected to theengagement member 312. The engagement member 312 includes complementarysets of teeth 324A, 324B to the teeth 322 on the drive member 304. Thesets of teeth 324A, 324B are located on opposite portions of theengagement member 312 and are offset slightly from one another. Upondepressing the push button 308 through the skin, the first set of teeth324A is released from the complementary teeth 322 on the drive member304 and, in turn, the second set of teeth 324B engage the complementaryteeth 322 of the drive member 304. Upon releasing the push button 308,the reset spring 310 causes the first set of teeth 324A to reengage withthe complementary teeth 322 and the second set of teeth 324B to releasefrom the complementary teeth 322. In this manner, the drive member 304is selectively released (e.g., a relatively small amount) following eachcycle of depressing and releasing the push button 308.

One of the connectors 22, such as the first connector 22A is secured tothe enlarged head 320. An aperture, roller, or other transition (notshown) is provided on the housing 302 such that the connector 22A isable to extend outwardly, in a transverse direction from the housing302. As the drive member 304 pistons downwardly out from the housing302, the enlarged head 320 moves downwardly, pulling the first connector22A into the housing 302 and reducing the effective length of the firstconnector 22A between the stabilizing member 12 and the first correctionanchor 18A, for example.

Though not shown, a magnetic latch assembly, such as those previouslydescribed, is optionally employed with this embodiment, or any otherappropriate embodiment, to help prevent inadvertent actuation of thetensioning system 300. Moreover, although the pushing force is suppliedby the drive spring 306, in other embodiments the pushing force issupplied by other potential energy drives, including expansion of ahydrogel material, gas (e.g., pre-installed in the first compartment302A or generated via chemical reaction, for example), or other meansfor generating a pushing force on the drive member 304.

FIGS. 16 and 17 show another tensioning system 350 that is optionallyemployed in addition to, or as a replacement for, one or more of thetensioners 20. The system 350, also described as a reciprocatingadjuster, includes a housing 352, a drive member 354, a one-way rollerclutch 356, also referred to as an outer clutch, a push button 358, areset spring 360, also described as a return mechanism, and a drivelinkage 362 coupling the push button 358 to the outer clutch 356 suchthat depression of the push button 358 (e.g., through the skin of apatient) results in rotational force on the outer clutch 356 in a firstdirection and releasing the push button 358 from the depressed positionto an initial position resulting in a rotational force on the outerclutch 356 in an opposite direction. The housing 352 generally maintainsthe outer clutch 356, the push button 358, the reset spring 360, and thedrive linkage 362, and is adapted to be secured (e.g., via a clamshellfit) to the stabilizing member 12.

The housing 352 is optionally substantially cylindrical and hollow,defining a first compartment 352A and a second compartment 352B. Thedrive member 354 is also optionally cylindrical and hollow, the drivemember 354 extending from the first compartment 352A out of the secondcompartment 352B of the housing 352, where the drive member 354 and thehousing 352 are coaxially received over the stabilizing member 12. Thedrive member 354 defines an enlarged base 366, a main body 368, and anenlarged head 370. In some embodiments, one or more of the connectors,such as the first connector 22A, is secured to the enlarged head 370.The main body 368 includes a plurality of threads 372 (FIG. 15) adaptedto mate with the outer clutch 356.

The drive member 354 is adapted to slide over the stabilizing member 12while the housing 352 is secured relative thereto, the drive member 354being able to slide out from the housing 352 until the enlarged headlimits further travel of the drive member 354. As shown, the outerclutch 356 is coaxially received over the drive member 354 between thebase 366 and the housing 352. The outer clutch 356 has a threadedinternal lumen (not shown), where the threads of the outer clutch 356mate with the threads 372 of the drive member 354 to move the drivemember 304 from a first position to a second position away from thehousing 352.

As shown in FIG. 17, the push button 358 is slidably received through asidewall of the second compartment 352B and is connected to the drivelinkage 362. Upon depressing the push button 308, the drive linkage 362causes the outer clutch 356 to rotate, or ratchet, until the push button308 is fully depressed. As the outer clutch 356 rotates, the drivemember 354 is driven out of the housing 352 and the first connector 22Ais pulled into the housing 352, thereby shortening its effective length.In at least this manner, the system 350 is optionally used to tensionthe first connector 22A to help correct a spinal deformity.

Though not shown, a magnetic latch assembly, such as those previouslydescribed, is optionally employed with this embodiment, or any otherembodiment described herein, to help prevent inadvertent actuation ofthe tensioning system 350.

FIGS. 18 and 19 show another tensioning system 400 that is optionallyemployed in addition to, or as a replacement for, one or more of thetensioners 20. The system 400, also described as a resistance adjuster,includes a hollow portion 402 of the stabilizing member 12, alsodescribed as a housing, a drive member 404, also described as a slideunit, a drive spring 406, also described as a potential energy drive, abiodegradable mass 408, also described as a resistance unit, a firstcollar 410, and a second collar 412.

As shown, the housing 402 defines a first compartment 402A and a secondcompartment 402B separated by a wall 402C having a lumen (not shown)sized to slidably receive the drive member 404. The housing 402 alsoincludes a first connector aperture 420 and a second connector aperture422, the first and second connector apertures 420, 422 being adapted toslidably receive one of the connectors 22, such as the first connector22A and the second connector 22B, for example.

As shown, the drive member 404 extends within the first compartment 402Aand the second compartment 402B, where the drive member 404 includes anenlarged base 426 slidably received in the second compartment 402B andabutted against the biodegradable mass 408.

The drive spring 406 is optionally a compression spring received overthe drive member 404, the drive spring 406 being positioned between theenlarged base 426 of the drive member 404 and the wall 402C.

In some embodiments, the biodegradable mass 408 is a polymeric materialconfigured to be absorbed into the body over a predetermined timeperiod. For example, in some embodiments, the biodegradable mass 408 isPGA (poly glycolic acid) with a degradation time between about 6 toabout 12 months, PLA (poly lactic acid) with a degradation time greaterthan about 24 months, or a bacterial polyester (e.g., apolyhydroxyalkanoate) with a degradation time greater than about 12months. The biodegradable mass 408 can be tailored (e.g., with apre-selected timing by combining different types of materials) todegrade over a predetermined time period. In some embodiments, one ormore portion(s) of the housing 402 allows bodily fluids to interact withthe biodegradable mass 408. For example, the second compartment 402Boptionally a porous wall structure or otherwise allows the body tointeract sufficiently with the biodegradable mass 408 to result inabsorption of the material.

The first and second collars 410, 412 are positioned along the drivemember 404 and, in some embodiments, are secured to the drive member 404such that the first and second collars 410, 412 move with the drivemember 404 as the drive member 404 slides in the housing 402. In turn,the first and second connectors 22A, 22B are secured to the first andsecond collars 410, 412.

In some implementations, the biodegradable mass 408 begins to beabsorbed over time, allowing the drive spring 406 to push the enlargedbase 426 downward, in turn causing the drive member 404 to slidedownward along with the first and second collars 410, 412. Generally,potential energy is stored in the drive spring 406 or other means forstoring energy (e.g., an expandable hydrogel) and is released at therate of decay of the biodegradable mass 408 (e.g., a substantiallycontinuous and predetermined rate of decay). The rate of decay ordegradation can be controlled by the type of biodegradable materialused, material geometry, the surface area exposed, the porosity of thematerial, and the shape of the biodegradable mass 408, for example.

In some embodiments, the axial movement of the drive member 404 drawsthe connectors 22A, 22B into the housing 202 through the first andsecond connector apertures 420, 422. As the connectors 22A, 22B aredrawn into the housing, the effective length between the connectors 22A,22B and the first and second correction anchors 18A, 18B is shortened,the correction anchors being drawn toward the housing 402, andconsequently, the stabilizing member 12. In at least this manner, thecorrection anchors 18 are able to be pulled toward the stabilizingmember 12, according to some embodiments.

FIGS. 20 and 21 show another tensioning system 450 that is optionallyemployed in addition to, or as a replacement for, one or more of thetensioners 20. The system 450, also described as a resistance adjuster,includes a housing 452 adapted to be received over the stabilizingmember 12, a drive member 454, also described as a slide unit, a drivespring 456, also described as a potential energy drive, and abiodegradable mass 458, also described as a resistance unit. In someembodiments, the system 450 generally operates similarly to the system400, where the system 450 is adapted to be secured over the stabilizingmember 12.

The housing 452 is optionally substantially cylindrical and hollow,defining a first compartment 452A. The drive member 454 extends from thefirst compartment 452A out of the housing 452, where the drive member454 and the housing 452 are coaxially received over the stabilizingmember 12. The drive member 454 is optionally substantially cylindricaland hollow and defines an enlarged base 466, a main body 468, and anenlarged head 470.

As shown, the drive member 454 is adapted to slide over the stabilizingmember 12 while the housing 452 is secured relative thereto, the drivemember 454 being able to slide out from the housing 452 until theenlarged head 470 limits further travel of the drive member 454. Asshown, the drive spring 456 is coaxially received over the drive member454 between the base 466 and the housing 452. The drive spring 456 is acompression spring for exerting a pushing force on the base 466 of thedrive member 454. The biodegradable mass 458 is located in the firstcompartment 452A between under the enlarged head 470 to substantiallyprevent the drive spring 456 from moving the drive member 454. As thebiodegradable mass degrades, the resistance to movement is removed andthe drive spring 456 is able to move the drive member 454 from a firstposition (FIG. 20) to a second position (FIG. 21) away from the housing452, although other types of springs are contemplated.

As the drive member 454 is selectively released (e.g., a predeterminedamount over time) following implantation of the system 450, the enlargedhead 470 moves within the first compartment 452A. In some embodiments,one or more of the connectors 22, such as the first connector 22A, issecured relative to the enlarged head 470. As the head 470 is actuatedwithin the first compartment 452A, the first connector 22A is drawn intothe housing 452, thereby shortening the effective length of the firstconnector 22A between the stabilizing member 12 and the first correctionanchor 18A. Thus, in some embodiments, the system 450 is optionallyemployed to draw one or more of the correction anchors 18 toward thestabilizing member 12.

FIGS. 22, 23, and 24 show another tensioning system 500 that isoptionally employed in addition to, or as a replacement for, one or moreof the tensioners 20. The system 500, also described as a resistanceadjuster, includes a housing 502 adapted to be received over thestabilizing member 12, a drive member 504, also described as a slideunit, a drive spring 506, also described as a potential energy drive, abiodegradable mass 508, also described as a resistance unit, a driveunit 510 connected to the drive member 504, and a guide piece 512. Insome embodiments, the system 500 generally operates similarly to thesystem 450, the system 500 being adapted to be secured over thestabilizing member 12.

The housing 502 is optionally substantially cylindrical and hollow,defining a first compartment 502A. The drive member 504 extends from thefirst compartment 502A out of the housing 502, where the drive member504 and the housing 502 are coaxially received over the stabilizingmember 12. The drive member 504 is optionally substantially cylindricaland hollow and defines an enlarged base 516, a main body 518, and anenlarged head 520.

As shown, the drive member 504 is adapted to slide over the stabilizingmember 12 while the housing 502 is secured relative thereto, the drivemember 504 being able to slide out from the housing 502 until theenlarged head 520 limits further travel of the drive member 504. Asshown, the drive spring 506 is coaxially received over the drive member504 between the base 516 and the housing 502. The drive spring 506 is acompression spring for exerting a pushing force on the base 516 of thedrive member 504. The biodegradable mass 508 is located in the firstcompartment 502A under the enlarged base 516 to substantially preventthe drive spring 456 from moving the drive member 504. As thebiodegradable mass 508 degrades, the drive spring 506 is able to movethe drive member 504 from a first position to a second position into thehousing 502, although other types of springs are contemplated.

As indicated in FIGS. 22 and 23, the drive unit 510 is connected to thedrive member 504, the drive unit being slidably received over thestabilizing member 12. The drive unit 510 includes an inner cylinder 530and with male threading and an outer cylinder 532 with female threadingcomplementary to the male threading on the inner cylinder 530. As shownin FIG. 24, the outer cylinder 532 includes an internal magnet 534adapted to interact with one or more external magnets 536 adapted to beactivated outside the patient, which, when rotated, rotationally drivethe internal magnet 534 through the skin of the patient, causing theouter cylinder 532 to be driven up or down the inner cylinder 530.

In some embodiments, the internal magnet 534 has a first portion of afirst polarity and a second portion of a second, opposite polarity. Theexternal magnets 536 similarly have two portions with oppositepolarities. As the external magnets 536 rotate, the polarities of theexternal magnets push and pull, respectively, on the polarities of theinternal magnet 534 as the external magnets are rotated. One example ofa suitable magnetic drive system is described in U.S. Patent ApplicationPublication 2009/0112207, filed May 15, 2008 and published Apr. 30,2009, the entire contents of which are incorporated herein by reference.

The guide piece 512 is adapted to be a low friction interface for one ormore of the connectors 22 adapted to direct the connectors 22 from anaxial direction along the stabilizing member 12 to a more transversedirection. One of the connectors 22, such as the first connector 22A, issecured to the outer cylinder 532 and up through the guide piece 512 toone of the correction anchors 18, such as the first correction anchor18A.

In some embodiments, the drive member 504 is selectively released (e.g.,a predetermined amount over time) following implantation of the system500 such that the enlarged head 520 moves further into the firstcompartment 502A. As the drive member 504 moves axially, so does thedrive unit 510, in turn pulling the connector 22A and shortening theeffective length of the connector 22A between the stabilizing member 12and the correction anchor 18A. As desired, the connector 22A is loosenedor tightened (e.g., for fine adjustment purposes), by using the externalmagnets 536 to rotate the internal magnet 534.

FIGS. 25 and 26 show another tensioning system 550 that is optionallyemployed in addition to, or as a replacement for, one or more of thetensioners 20. In some embodiments, the system 550, also described as aresistance adjuster, includes a housing 552 adapted to be received overthe stabilizing member 12, a coupler 554, also described as a slideunit, a drive spring 556, also described as a potential energy drive,and a biodegradable mass 558, also described as a resistance unit.

In some embodiments, the housing 552 is adapted to be secured to thestabilizing member 12 (e.g., via a clamshell fit) and includes asubstantially helical internal compartment 552A with a connectoraperture 570 opening into the internal compartment 552A. As shown, thedrive spring 556 is helically wound in the internal compartment 552A andis adapted to act as a torsion spring, the drive spring 556 being in acompressed state with a first end 572 of the spring 556 secured to thehousing 552 and a second end 574 of the spring 556 connected to thecoupler 554. In some embodiments, the biodegradable mass 558 is disposedat the second end 574 of the spring 556 and/or the coupler 554,maintaining the spring 556 in a compressed state. One of the connectors22, such as the first connector 22A, is secured to the coupler 554, thefirst connector 22A winding back out of the internal compartment 552Athrough the connector aperture 570.

In some embodiments, as the biodegradable mass 558 degrades, the secondend 570 of the spring 556 travels further into the internal compartment552A, drawing the coupler 554 and the first connector 22A further intothe internal compartment 552A. In some embodiments, as the firstconnector 22A is drawn into the internal compartment 552A, the effectivelength between the stabilizer 12 and the correction anchor 18A isreduced.

FIGS. 27 and 28 show an expanding stabilizing member system 600 that isoptionally employed in addition to, or as a replacement for, thestabilizing member 12. For example, the system 600, also described as aresistance adjuster, is optionally employed by attaching the system 600to the spinal column 24 using the stabilizing anchors 18, such that thespinal column 24 is able to be expanded longitudinally to help reducethe defective curvature of the spinal column 24.

In some embodiments, the system 600 includes a housing 602, a drivemember 604, also described as a slide unit, a drive spring 606, alsodescribed as a potential energy drive, a biodegradable mass 608, alsodescribed as a resistance unit, and an adjustable collar 610. Thehousing 602 is optionally substantially cylindrical and hollow, defininga first compartment 602A. The drive member 604 extends from the firstcompartment 602A out of the housing 602. The drive member 604 isoptionally substantially cylindrical and defines a main body 612 havinga plurality of male threads along the length thereof (not shown) and anenlarged head 614.

In some embodiments, the adjustable collar 610 has female threading andis coaxially received over the male threading of the main body 612. Theadjustable collar 610 includes a magnetic element and/or is otherwiseadapted to respond to magnetic force, the adjustable collar 610 having afirst polarity portion 610A and a second polarity portion 610B.

As shown, the drive member 604 is adapted to slide within the housing602. In some embodiments, the drive member 604 is restricted fromrotating relative to the drive housing, for example, being keyed orotherwise having complementary features to the portion of the housing602 from which the drive member 604 extends that substantially preventrelative rotation between the housing and drive member 604. The drivemember 604 is adapted to slide out from the housing 602 until theadjustable collar 610 limits further travel of the drive member 604 andinto the housing 602 until the enlarged head 614 abuts the housing 602.

As shown, the drive spring 606 is coaxially received over the drivemember 604 between the adjustable collar 610 and the housing 602. Thedrive spring 606 is a compression spring for exerting a pushing force onthe adjustable collar 610 of the drive member 604. The biodegradablemass 608 is located in the first compartment 602A ahead of theadjustable collar 610 to substantially prevent the drive spring 606 frommoving the drive member 604. As the biodegradable mass 608 degrades, thedrive spring 606 is able to move the drive member 604 from a firstposition to a second position outwardly from the housing 602, to extendthe overall length of the system 600.

In some embodiments, the effective length of the system 600 is adjusted(e.g., for fine adjustments or if the length of the system begins togrow too quickly), by rotating the adjustable collar 610. In someembodiments, an external magnetic drive 640, such as those previouslydescribed, is utilized through the skin to rotate the adjustable collar610 and adjust the overall length of the system 600.

Although potential energy is stored in the system 600 using the spring606, in other embodiments an expanding material, is utilized to exert apushing force on the drive member 604. For example a hydrogel material(e.g., material having the tradename “HYPAN” available from Hymedix),NDGA (nordihydroguaiaretic acid), and/or other expandable materials areoptionally utilized. In still other embodiments, the spring 606 isreplaced and/or augmented by using a compressed gas cylinder or othermeans for storing potential energy for use in the system 600 to drivethe drive member 604.

FIG. 29 shows another tensioning system 650 that is optionally employedin addition to, or as a replacement for, one or more of the tensioners20. For example, the tensioning system 650 optionally replaces thestabilizing member 12 or portions thereof, or is mounted to thestabilizing member 12 as desired. The system 650 includes a housing 652,a drive member 654, a first actuator collar 656, a second actuatorcollar 658, a motor unit 660 connected to the drive member 654, and apower coupler 662.

In some embodiments, the housing 652 includes a substantially hollowvertical rod (e.g., about 10-15 mm in diameter), the housing 652 beingadapted to maintain the drive member 654, the first and second actuatorcollars 656, 658, and the motor unit 660. The housing 652 optionallyacts as the stabilizing member 12 in the system 10, in some embodiments,the housing being secured to the spinal column 24 with the stabilizinganchors 18, for example.

The drive member 654 is optionally adapted to act as a substantiallyflexible axle, for example being about 3 mm in diameter and formed ofsteel or other appropriate material (e.g., metallic and/or polymericmaterials). The actuator collars 656, 658 are secured to the drivemember 654 at longitudinal positions thereon and one or more of theconnectors 22, such as the first and second connectors 22A, 22B,respectively, are secured to the actuator collars 656, 658.

The first and second actuator collars 656, 658 are optionallysubstantially similar, the first and second actuator collars 656, 658being described cumulatively with respect to the first actuator collar656. In some embodiments, the first actuator collar 656 is amagnetically activated tensioner means secured to one of the connectors22, such as the first connector 22A.

The first actuator collar 656 is shown in FIGS. 30 and 31, where FIG. 30shows the first actuator collar 656 in a free spinning, or unlockedstate, and FIG. 31 shows the first actuator collar 656 in a locked, orengaged state. As shown, the first actuator collar 656 includes an outerportion 656A and an inner portion 656B having a plurality of pocketsslidably receiving a plurality of magnetic engagement members 670. Asshown in FIG. 31, an external magnet 672 is brought into proximity of apatient (not shown) to cause the magnetic engagement members 670 to pushinwardly to lock the inner and outer portions 656A, 656B.

In some embodiments, the magnetic polarity on the external magnet 672 isswitched (by physically flipping a magnet or switching the current to anelectric magnet) in order to cause the magnetic engagement members 670to slide outwardly into the pockets in the outer portion 656A to releasethe first actuator collar 656. As described further below, magneticactivation of the actuator collars 656, 658 helps facilitate individualadjustment, allowing more torque from a single source to be available todraw the connectors 22 to the housing 652.

In some embodiments, the motor unit 660 is a Maxon Motor, 13 mm OD, witha 3371:1 gear ratio, although a variety of motors are optionallyemployed. The power coupler 662 is optionally an inductive powercoupler, also described as a receiver, a secondary coil, or an internalantenna, for receiving inductive power from an external inductive powersource (not shown). In some embodiments, the power coupler 662 has abouta 50 mm diameter body and includes a physical magnet such that theexternal inductive power source, or external primary coil, is betterable to center on the power coupler 662 to increase the couplingefficiency.

In some embodiments, when the external, primary coil (not shown) iscentered above the power coupler 662, electrical energy on the order of2-3 watts (up to 20 watts if needed) is delivered to the motor unit 660causing rotation of the drive member 654. The connectors 22 areselectively tensioned by engaging a selected one of the actuator collars656, 658 magnetically. In at least this manner, power is selectivelyapplied for tensioning so that the maximum amount of tension is directedto the desired connector 22. If desired, the motor unit 660 isreversible and/or gearing (not shown) is employed to pay out, or loosenthe connectors 22 as desired. In some embodiments, feedback and positioninformation is transmitted back from the system 650 to an externalreceiver via IR (infrared) or RF (radio frequency), for example.

FIG. 32 shows another tensioning system 700 that is optionally employedin addition to, or as a replacement for, one or more of the tensioners20. For example, the tensioning system 700 optionally replaces thestabilizing member 12 or portions thereof, or is mounted to thestabilizing member 12 as desired. The system 700 includes a secondaryspool 702, a drive member 704, a first actuator collar 706, a secondactuator collar 708, a motor unit 710 connected to the drive member 704,a power coupler 712, and a gear system 714. Although the power coupler712 is optionally an inductive power source, in other embodiments thepower coupler is an implantable battery or other power source.

As shown, the system 700 operates generally similarly to the system 650.In some embodiments, the drive member 704 and the secondary spool 702are interconnected by the gear system 714. The motor unit 710 turns thedrive member 704, which, through the gear system 714, turns thesecondary spool 702. The first and second actuator collars 706, 708 aresecured to the secondary spool 702 and are thereby turned to draw one ormore of the connectors 22 toward the secondary spool 702. Additionally,the secondary spool 702 is optionally turned in an opposite direction topay out the connectors 22 from the actuator collars 706, 708 as desired.Magnetic means (not shown) are optionally employed to engage ordisengage the actuator collars 706, 708 as desired.

FIGS. 33 and 34 show another tensioning system 750 that is optionallyemployed in addition to, or as a replacement for, one or more of thetensioners 20. For example, the tensioning system 750 optionallyreplaces the stabilizing member 12 or portions thereof, or is mounted tothe stabilizing member 12 as desired. The system 750 includes a housing752, a drive member 754, a first actuator collar 756, a second actuatorcollar 758, a motor unit 760 connected to the drive member 754, and apower coupler 762.

In some embodiments, the housing 752 includes a substantially hollowvertical cylindrical body (e.g., about 10-15 mm in diameter), thehousing 752 being adapted to house the drive member 754, the first andsecond adjustment collars 756, 758, and the motor unit 760. The housing752 optionally acts as the stabilizing member 12 in the system 10, insome embodiments, the housing being secured to the spinal column 24 withthe stabilizing anchors 18, for example.

As shown, the drive member 754 includes two portions, a base portion754A and a traveler portion 754B. The base portion 754A is elongate andextends from a first end 770 connected to the motor unit 760 and asecond end 772 bearing a male threaded head 774. The traveler portion754A is substantially elongate and includes a female threaded section778 and a carrier section 780. The traveler portion 754B isnon-rotatable and axially slidable in the housing 752. The femalethreaded section 778 of the traveler portion 754B is mated with the malethreaded head 774 of the base portion 754A such that rotation of thebase portion 754A by the motor unit 760 causes the traveler portion 754Bto move axially within the housing 752. For example, FIG. 33 shows thetraveler portion 754B at a first position in the housing 752 and FIG. 34shows the traveler portion 756B in a second, more retracted position inthe housing 752.

The adjustment collars 756, 758 are secured at longitudinal positionsalong the carrier section 780. One or more of the connectors 22 aresecured to each of the adjustment collars, such as the first and secondconnectors 22A, 22B, respectively, such that axial movement of thecarrier section 780 draws in or lets out the connectors 22 from thehousing 752, thereby shortening or lengthening the effective length ofthe connectors 22 between the correction anchors 18 and the housing 752as desired. In some embodiments, the adjustment collars 756, 758 arealso threaded onto the carrier section 780, where rotation of theadjustment collars 756, 758 using external magnets such as thosepreviously referenced, allows additional tensioning and/or loosening ofthe connectors 22.

FIGS. 35 and 36 show another tensioning system 800 that is optionallyemployed in addition to, or as a replacement for, one or more of thetensioners 20. For example, the tensioning system 800 optionallyreplaces the stabilizing member 12 or portions thereof, or is mounted tothe stabilizing member 12 as desired. The system 800 includes a housing802, a drive member 804, a first actuator anchor 806, a second actuatoranchor 808, a motor unit 810 connected to the drive member 804, and apower coupler 812.

In some embodiments, the housing 802 includes a substantially hollowvertical cylindrical body (e.g., about 10-15 mm in diameter) having aplurality of connector apertures 816, the housing 802 being adapted tohouse the drive member 804, the first and second adjustment anchors 806,808, and the motor unit 810. The housing 802 optionally acts as thestabilizing member 12 in the system 10. In some embodiments, the housing802 is secured to the spinal column 24 with the stabilizing anchors 18,for example.

As shown, the drive member 804 includes two portions, a base portion804A and a traveler portion 804B. The base portion 804A is elongate andextends from a first end 820 connected to the motor unit 810 and asecond end 822 bearing a male threaded head 824. The traveler portion804A is substantially elongate and includes a female threaded section828 and a carrier section 830. The traveler portion 804B isnon-rotatable and axially slidable in the housing 802. The femalethreaded section 828 of the traveler portion 804B is mated with the malethreaded head 824 of the base portion 804A such that rotation of thebase portion 804A by the motor unit 810 causes the traveler portion 804Bto move axially within the housing 802. For example, FIG. 35 shows thetraveler portion 804B at a first position in the housing 802 and FIG. 36shows the traveler portion 806B in a second, more retracted position inthe housing 802.

As shown, the first and second adjustment anchors 806, 808 aresubstantially similar to one another. As such, the second adjustmentanchor 808 is described cumulative with respect to the first adjustmentanchor 806. The first and/or second adjustment anchors 806, 808 areoptionally adapted to be substituted for one or more of the correctionanchors 18, according to some embodiments. As shown, the firstadjustment anchor 806 is generally L-shaped when viewed from the side,where the first adjustment anchor 806 includes an extension arm 806Awith male threading (not shown), a collar 806B with female threading(not shown), a base arm 806C, and a head 806D all assembled together.

The collar 806B is rotatably coupled to the base arm 806C and theextension arm 806A is non-rotatably and slidably coupled to the base arm806C. The extension arm 806A is received within the collar 806B and thebase arm 806C. The threads of the extension arm 806A and the collar 806Bare mated such that the extension arm 806A is able to be telescopedinward and outward from the collar 806B and the base arm 806C byrotating the collar 806B in a first direction and a second direction,respectively. The collar 806B is optionally formed of a magneticmaterial and has a portion with a first polarity and another portionwith a second polarity. External magnets (not shown), such as thosepreviously described, are optionally used to rotate the collar 806B toadjust the overall length of the adjustment anchor 806.

The head 806D of the adjustment anchor 806 optionally includes a pediclescrew that is adapted to be driven into a vertebra of the spinal column24 such that the adjustment anchor 806 is able to be pulled uponsimilarly to one of the correction anchors 18.

One or more of the connectors 22 are secured to the carrier section 830,respectively, such that axial movement of the carrier section 830 drawsin or lets out the connectors 22 from the connector apertures 816 of thehousing 802, thereby shortening or lengthening the effective length ofthe connectors 22 between the adjustment anchors 806A, 806B and thehousing 802, and thus the spinal column 24, as desired. Each of theadjustment anchors 806A, 806B are also optionally adjusted in length tomodify the tension being exerted by the system 800 on the spinal column24 as desired.

FIGS. 37 and 38 show another tensioning system 850 that is optionallyemployed as a means for externally operating the tensioners 20. Asshown, the system 850, also described as a reciprocating adjuster,includes a housing 852, a motor drive 854, a power coupler 856, a rollerclutch 858, and a drive shaft 860.

The housing 852 is adapted to maintain the motor drive 854, the rollerclutch 858, and the drive shaft 860. The motor drive 854 is optionally anitinol drive, such as that sold under the trade name “DM01 nitinolactuator” from “MIGA MOTORS.” The motor drive 854 includes an actuationarm 854A and a return spring 854B, also described as a return mechanism,connected on opposite sides of the roller clutch 858.

The power coupler 856 is optionally similar to those previouslydescribed (e.g., an induction coil) and, when electrical energy isapplied, the nitinol of the motor drive 854 is heated, causingcontraction of the actuation arm 854A which pulls the actuation arm 854A(e.g., with about 7 lbs of force). The actuation arm 854A is connectedto the roller clutch 858, which is a one-way roller clutch, such thatretraction of the actuation arm 854A causes rotation of the one-wayroller clutch 858. When the nitinol cools the return spring 854B presseson the opposite side of the roller clutch 858 such that the actuationarm 854A returns to the original position where the actuation arm 854Ais able to be actuated again by activating the motor drive 854,generating a ratcheting effect. The drive shaft 860 is coupled to theroller clutch 858 such that ratcheting of the roller clutch ratchets thedrive shaft 860.

The drive shaft 860 is adapted to be connected to the actuation head ofone of the tensioners 20, such as the first tensioner 20A, for example,by including a suitable mating component, such as a hex head driver, orby being integrally formed or otherwise connected to the actuation head,such as the actuation head 78A (FIG. 3). In some embodiments, thehousing 856 of the implantable driver 852 is secured to the housing 80Aand/or the stabilizing member 12, for example being integrally formedtherewith.

FIGS. 39, 40, and 41 show an expanding stabilizing member system 900that is optionally employed in addition to, or as a replacement for, thestabilizing member 12. For example, the system 900, also described as areciprocating adjuster and a resistance adjuster, is optionally employedby attaching the system 900 to the spinal column 24 (FIG. 1) using thestabilizing anchors 18, such that the spinal column 24 is able to beexpanded longitudinally to help reduce the defective curvature of thespinal column 24.

In some embodiments, the system 900 includes a housing 902, a drivemember 904, also described as a slide unit, a drive spring 906, alsodescribed as a potential energy drive, and a magnetic walker assembly908, also described as a resistance unit. The drive member 904 isoptionally substantially cylindrical and includes a plurality of surfacegrooves 910 along the length of the drive member 904, the surfacegrooves 910 being adapted to mate with the magnetic walker assembly 908which acts as both a piston and a return mechanism. In some embodiments,the drive spring 906 is received within the housing 902 between the endof the drive member 904 and the housing 902. The drive spring 906 is acompression spring for exerting a pushing force on the drive member 904.As shown, the drive member 904 extends from the housing 902, the drivemember 904 being adapted to slide within the housing 902 when notrestricted by the magnetic walker assembly 908.

In some embodiments, the magnetic walker assembly 908 is secured to thehousing 902 and includes a first receptacle 916 holding a first toothedmember 918 and a second receptacle 920 holding a second toothed member922. Each of the first and second toothed members 918, 922 are biased inthe downward position (e.g., by a spring—not shown), the first andsecond toothed members 918, 922 each including a plurality of teeth918A, 922A for mating with the surface grooves 910. In some embodiments,each of the first and second toothed members displays a differentpolarity from the other. In some embodiments, each of the toothedmembers 918, 922 is substantially arcuately shaped to increase thesurface engagement with the surface grooves 910.

An external magnet 930 having a first polarity portion 932 and a second,opposite polarity portion 934 is optionally employed through the skin toalternately actuate the first and second toothed members 918, 922 intoand out of the surface grooves 910. In some embodiments, the effectivelength of the system 900 is adjusted by alternatively actuating thefirst and second toothed members 918, 922 to “walk” the drive member 904outwardly from the housing 902, where the potential energy representedin the system 900 by the spring 906 is released as the toothed members918, 922 engage and release the surface grooves 910. Although a springis used in some embodiments, in other embodiments an expanding material,such as those previously described, is utilized to exert a pushing forceon the drive member 904. FIGS. 40 and 41 are illustrative of thealternate engagement of the first toothed member, those figures showingthe external magnet 930, the drive member 904, and the first toothedmember 918 with other portions removed for ease of illustration. FIG. 40shows the first toothed member 918 in an engaged position and FIG. 41shows the external magnet 930 rotated 180 degrees such that the firsttoothed member 918 is actuated to a disengaged position.

FIGS. 42 and 43 show another expanding stabilizing member system 950that is optionally employed in addition to, or as a replacement for, thestabilizing member 12. For example, the system 950, also described as areciprocating adjuster and a resistance adjuster, is optionally employedby attaching the system 950 to the spinal column 24 (FIG. 1) using thestabilizing anchors 18, such that the spinal column 24 is able to beexpanded longitudinally using the system 950 to help reduce thedefective curvature of the spinal column 24.

Similarly to the system 900, in some embodiments, the system 950includes a housing 952, a drive member 954, also described as a slideunit, a drive spring 956, also described as a potential energy drive,and a magnetic walker assembly 958, also described as a resistance unit,that acts as a drive piston and a return mechanism.

As shown, the magnetic walker assembly 958 is secured to the housing 952and includes a receptacle 966 holding a first toothed member 968 and asecond toothed member 972, the first and second toothed members 968, 972being positioned on an arm that is hinged to the receptacle 966. Each ofthe first and second toothed members 968, 972 is biased in the downwardposition (e.g., by a spring—not shown), the first and second toothedmembers 968, 972 each including one or more teeth 968A, 972A for matingwith the surface grooves 960. In some embodiments, each of the first andsecond toothed members 968, 970 is characterized by a different polarityfrom the other. In some embodiments, each of the toothed members 968,972 is substantially arcuately shaped to increase the surface engagementwith the surface grooves 960.

A principle of operation of the system 950 is illustrated more generallyin FIG. 44. As shown, an external magnet 980 having a first polarityportion 982 and a second, opposite polarity portion 984 is optionallyemployed through the skin (not shown) to alternately actuate the firstand second toothed members 968, 972 into and out of the surface grooves960. In some embodiments, the effective length of the system 950 isadjusted by alternatively actuating the first and second toothed members968, 972 to “walk” or “step” the drive member 954 outwardly from thehousing 952, where the potential energy represented in the system 950 bythe spring 956 is released as the toothed members 968, 972 alternatelyengage and release the surface grooves 960, the two members 968, 972alternatively acting as piston unit and a return mechanism. Although aspring is used in some embodiments, in other embodiments an expandingmaterial, such as those previously described, is utilized to exert apushing force on the drive member 954. As an alternative to a physicalmagnet, the external magnet 980 is optionally an electric magnet that isable to switch polarities for stepping the system 950 at a desiredelectromagnetic force and speed.

Some embodiments apply the magnetic stepping, or walking, operationdescribed in association with systems 900 and 950 for another tensioningsystem 1000 shown in FIGS. 45 and 46, the system 1000 being optionallyemployed in addition to, or as a replacement for, one or more of thetensioners 20. As shown, the system 1000, also described as areciprocating adjuster and a resistance adjuster, includes a housing1002, a drive member 1004, also described as a slide unit, a drivespring 1006, also described as a potential energy drive, and a magneticwalker assembly 1008, also described as a resistance unit. The drivemember 1004 is optionally configured with surface grooves similar tothose of the systems 900 and 950 and the magnetic walker assembly 1008,acting as a piston unit and a return mechanism, is optionally adapted tointeract with the drive member 1004 similarly to those of the systems300, 900 and/or 950. Upon application of a magnetic force of alternatingpolarity (schematically indicated by external magnet 1020 in FIG. 44),the system 1000 operates similarly to the system 300 described above.

For example, the drive member 1004 is adapted to slide over thestabilizing member 12 while the housing 1002 is secured relativethereto, the drive member 1004 being able to slide out from the housing1002 until an enlarged head 1020 of the drive member 1004 limits furthertravel of the drive member 1004. As shown, the drive spring 1006 iscoaxially received over the drive member 1004 between the base 1016 andthe housing 1002. The drive spring 1006 is a compression spring forexerting a pushing force on a base 1016 of the drive member 1004, tomove the drive member 1004 from a first position (FIG. 45) to a secondposition (FIG. 46) away from the housing 1002, although other types ofsprings are contemplated.

One of the connectors 22, such as the first connector 22A is secured toan enlarged head 1022 of the drive member 1004. An aperture, roller, orother feature (not shown) is provided on the housing 1002 such that theconnector 22A is able to extend outwardly, in a transverse directionfrom the housing 1002. As the drive member 1004 pistons downwardly outfrom the housing 1002, the enlarged head 1022 moves downwardly, pullingthe first connector 22A into the housing 1002 and reducing the effectivelength of the first connector 22A between the stabilizing member 12 andthe first correction anchor 18A, for example.

According to the foregoing, various embodiments relate to a spinalcorrection system for implantation in a patient, the system including acorrection anchor, a stabilizing member, a reciprocating adjuster, and aconnector. The correction anchor is configured to be secured to avertebra in a defect area of a spine. The stabilizing member isconfigured to be secured against translation at the defect area of thespine. The reciprocating adjuster is coupled to the stabilizing member,the reciprocating adjuster including: a piston unit displaceable in afirst direction, and a transfer unit coupled to the piston unit suchthat displacement of the piston unit in the first direction causes thetransfer unit to be displaced in a second direction. The connectorextends from the reciprocating adjuster to define an effective lengthbetween the reciprocating adjuster and the correction anchor, theconnector having a first end configured to be coupled to the transferunit and a second end configured to be coupled to the correction anchorsuch that displacement of the transfer unit causes shortening of theeffective length of the connector.

In some embodiments, the piston unit includes a depressible shaft andthe transfer unit includes a roller.

In some embodiments, the roller is a one-way drive clutch.

In some embodiments, the system is configured such that displacement ofthe roller winds the connector about the roller.

In some embodiments, the piston unit includes gearing and the transferunit includes gearing for mating with the gearing of the piston unit.

In some embodiments, the piston unit includes a tooth member and thetransfer unit includes a plurality of surface grooves configured to matewith the tooth member such that, upon displacement of the piston unit,the tooth member mates with the groove to displace the transfer unit.

In some embodiments, the piston unit is displaceable between a firstposition and a second position and the piston unit includes a returnmechanism for returning the piston unit from the second position to thefirst position.

In some embodiments, the return mechanism includes a spring.

In some embodiments, the piston unit is coupled to a magnetic member.

In some embodiments, the system further comprises an external magneticdrive for actuating the piston unit by displacing the magnetic member.

In some embodiments, the system further comprises an implantable motorand an implantable power source, the motor being coupled to the pistonunit.

In some embodiments, the power source includes an internal antennae forreceiving inductive power.

In some embodiments, the power source includes an implantable battery.

According to the foregoing, various embodiments relate to a method ofcorrecting a spine, the method including securing a correction anchor toa vertebra in a defect area of a spine and securing a stabilizing memberagainst translation at the defect area of the spine. A piston unit of areciprocating adjuster is displaced in a first direction to cause atransfer unit of the reciprocating adjuster to be displaced in a seconddirection, in turn, causing shortening of an effective length of aconnector coupling the correction anchor and the reciprocating adjuster.

According to the foregoing, various embodiments relate to a spinalcorrection system for implantation in a patient, the system including acorrection anchor, a stabilizing member, a resistance adjuster, and aconnector. The correction anchor is configured to be secured to avertebra in a defect area of a spine. The stabilizing member isconfigured to be secured against translation at the defect area of thespine. The resistance adjuster is coupled to the stabilizing member, theresistance adjuster including: a potential energy drive, a slide unitcoupled to the potential energy drive such that the potential energydrive exerts a displacement force on the slide unit biasing the slideunit in a first direction, and a resistance unit coupled to the slideunit, the resistance unit being configured to selectively oppose thedisplacement force. The connector extends from the resistance adjusterto define an effective length between the resistance adjuster and thecorrection anchor, the connector having a first end configured to becoupled to the slide unit and a second end configured to be coupled tothe correction anchor such that displacement of the slide unit in thefirst direction causes shortening of the effective length of theconnector.

In some embodiments, the potential energy drive is received coaxiallyabout the slide unit.

In some embodiments, the resistance unit includes a tooth member and theslide unit includes a plurality of surface grooves configured to matewith the tooth member such that upon displacing the tooth memberlongitudinally from a first position to a second position releases theresistance unit.

In some embodiments, the potential energy drive includes an expandingmaterial.

In some embodiments, the expanding material is temperature activated.

In some embodiments, the expanding material is fluid activated.

In some embodiments, the potential energy drive includes a spring.

In some embodiments, the resistance unit includes hydrogel material.

In some embodiments, the resistance unit includes a biodegradablematerial.

In some embodiments, the resistance unit is coupled to a magneticmember.

In some embodiments, the system further comprises an external magneticdrive for actuating the slide unit by displacing the magnetic member.

In some embodiments, the external magnetic drive includes a rotatingmagnet.

In some embodiments, the system further comprises an implantable motorand an implantable power source, the motor being coupled to the pistonunit.

In some embodiments, the power source includes an internal antennae forreceiving inductive power.

In some embodiments, the power source includes an implantable battery.

According to the foregoing, various embodiments relate to a method ofcorrecting a spine, the method including securing a correction anchor toa vertebra in a defect area of a spine and securing a stabilizing memberagainst translation at the defect area of the spine. The method alsoincludes actuating a resistance unit of a resistance adjuster coupled tothe stabilizing member such that the resistance adjuster selectivelyreleases a displacement force provided by a potential energy drivecoupled to a slide unit, the slide unit being displaced by the potentialenergy drive in a first direction to cause shortening in an effectivelength of a connector coupled between the resistance adjuster and thecorrection anchor.

According to the foregoing, various embodiments relate to a spinalcorrection system for implantation in a patient, the system including acorrection anchor, a stabilizing member, a resistance adjuster, and aconnector. The correction anchor is configured to be secured to avertebra in a defect area of a spine. The stabilizing member isconfigured to be secured against translation at the defect area of thespine. The resistance adjuster is coupled to the stabilizing member, theresistance adjuster including: a potential energy drive including anexpanding material configured to expand after being subjected to aninternal body environment of the patient and a slide unit coupled to thepotential energy drive such that the potential energy drive exerts adisplacement force on the slide unit biasing the slide unit in a firstdirection. The connector extends from the resistance adjuster to definean effective length between the resistance adjuster and the correctionanchor, the connector having a first end configured to be coupled to theslide unit and a second end configured to be coupled to the correctionanchor such that displacement of the slide unit in the first directioncauses shortening of the effective length of the connector.

Various modifications and additions can be made to the exemplaryembodiments discussed without departing from the scope of the presentinvention. For example, while the embodiments described above refer toparticular features, the scope of this invention also includesembodiments having different combinations of features and embodimentsthat do not include all of the described features. Accordingly, thescope of the present invention is intended to embrace all suchalternatives, modifications, and variations as fall within the scope ofthe claims, together with all equivalents thereof.

We claim:
 1. A spinal correction system for implantation in a patient,the system comprising: a correction anchor configured to be secured to avertebra in a defect area of a spine; a stabilizing member configured tobe secured against translation at the defect area of the spine; areciprocating adjuster coupled to the stabilizing member, thereciprocating adjuster including: a piston unit displaceable in a firstdirection, and a transfer unit coupled to the piston unit such thatdisplacement of the piston unit in the first direction causes thetransfer unit to be displaced in a second direction; and a connectorextending from the reciprocating adjuster to define an effective lengthbetween the reciprocating adjuster and the correction anchor, theconnector having a first end configured to be coupled to the transferunit and a second end configured to be coupled to the correction anchorsuch that displacement of the transfer unit causes shortening of theeffective length of the connector, wherein the piston unit includes adepressible shaft and the transfer unit includes a roller.
 2. The systemof claim 1, wherein the roller is a one-way drive clutch.
 3. The systemof claim 1, configured such that displacement of the roller winds theconnector about the roller.
 4. The system of claim 1, wherein the pistonunit includes gearing and the transfer unit includes gearing for matingwith the gearing of the piston unit.
 5. The system of claim 1, whereinthe piston unit includes a tooth member and the transfer unit includes aplurality of surface grooves configured to mate with the tooth membersuch that, upon displacement of the piston unit, the tooth member mateswith the groove to displace the transfer unit.
 6. The system of claim 1,wherein the piston unit is displaceable between a first position and asecond position and the piston unit includes a return mechanism forreturning the piston unit from the second position to the firstposition.
 7. The system of claim 6, wherein the return mechanismincludes a spring.
 8. The system of claim 1, wherein the piston unit iscoupled to a magnetic member.
 9. The system of claim 8, furthercomprising an external magnetic drive for actuating the piston unit bydisplacing the magnetic member.
 10. The system of claim 1, furthercomprising an implantable motor and an implantable power source, themotor being coupled to the piston unit.
 11. The system of claim 10,wherein the power source includes an internal antennae antenna forreceiving inductive power.
 12. The system of claim 10, wherein the powersource includes an implantable battery.
 13. A method of correcting aspine, the method comprising: securing a correction anchor to a vertebrain a defect area of a spine; securing a stabilizing member againsttranslation at the defect area of the spine; and displacing adepressible shaft in a piston unit of a reciprocating adjuster in afirst direction to cause a roller in a transfer unit of thereciprocating adjuster to be displaced in a second direction, in turn,causing shortening of an effective length of a connector coupling thecorrection anchor and the reciprocating adjuster.
 14. A spinalcorrection system for implantation in a patient, the system comprising:a correction anchor configured to be secured to a vertebra in a defectarea of a spine; a stabilizing member configured to be secured againsttranslation at the defect area of the spine; a resistance adjustercoupled to the stabilizing member, the resistance adjuster including: apotential energy drive, a slide unit coupled to the potential energydrive such that the potential energy drive exerts a displacement forceon the slide unit thereby biasing the slide unit in a first direction,and a resistance unit coupled to the slide unit, the resistance unitbeing configured to selectively oppose the displacement force; and aconnector extending from the resistance adjuster to define an effectivelength between the resistance adjuster and the correction anchor, theconnector having a first end configured to be coupled to the slide unitand a second end configured to be coupled to the correction anchor suchthat displacement of the slide unit in the first direction causesshortening of the effective length of the connector.
 15. The system ofclaim 14, wherein the potential energy drive is received coaxially aboutthe slide unit.
 16. The system of claim 14, wherein the resistance unitincludes a tooth member and the slide unit includes a plurality ofsurface grooves configured to mate with the tooth member such that uponlongitudinal displacement of the tooth member from a first position to asecond position releases the resistance unit.
 17. The system of claim14, wherein the potential energy drive includes an expanding material.18. The system of claim 17, wherein the expanding material istemperature activated.
 19. The system of claim 17, wherein the expandingmaterial is fluid activated.
 20. The system of claim 14, wherein thepotential energy drive includes a spring.
 21. The system of claim 14,wherein the resistance unit includes hydrogel material.
 22. The systemof claim 14, wherein the resistance unit includes a biodegradablematerial.
 23. The system of claim 14, wherein the resistance unit iscoupled to a magnetic member.
 24. The system of claim 23, furthercomprising an external magnetic drive for actuating the slide unit bydisplacing the magnetic member.
 25. The system of claim 24, wherein theexternal magnetic drive includes a rotating magnet.
 26. The system ofclaim 14, further comprising an implantable motor and an implantablepower source, the motor being coupled to the piston unit.
 27. The systemof claim 26, wherein the power source includes an internal antenna forreceiving inductive power.
 28. The system of claim 26, wherein the powersource includes an implantable battery.
 29. A method of correcting aspine, the method comprising: securing a correction anchor to a vertebrain a defect area of a spine; securing a stabilizing member againsttranslation at the defect area of the spine; and actuating a resistanceunit of a resistance adjuster coupled to the stabilizing member suchthat the resistance adjuster selectively releases a displacement forceprovided by a potential energy drive coupled to a slide unit, the slideunit being displaced by the potential energy drive in a first directionto cause shortening in an effective length of a connector coupledbetween the resistance adjuster and the correction anchor.
 30. A spinalcorrection system for implantation in a patient, the system comprising:a correction anchor configured to be secured to a vertebra in a defectarea of a spine; a stabilizing member configured to be secured againsttranslation at the defect area of the spine; a resistance adjustercoupled to the stabilizing member, the resistance adjuster including: apotential energy drive including an expanding material configured toexpand after being subjected to an internal body environment of thepatient, and a slide unit coupled to the potential energy drive suchthat the potential energy drive exerts a displacement force on the slideunit thereby biasing the slide unit in a first direction, and aconnector extending from the resistance adjuster to define an effectivelength between the resistance adjuster and the correction anchor, theconnector having a first end configured to be coupled to the slide unitand a second end configured to be coupled to the correction anchor suchthat displacement of the slide unit in the first direction causesshortening of the effective length of the connector.